FIG. 4 is a diagrammatic view showing the construction and operation of a conventional chip mounter. As shown in FIG. 4 a conventional chip mounter 10 mounts electronic components or chips 12 on a print-circuit board (PCB) or printed board 18 horizontally located on a bed 16 comprising, for example, a conveyer.
The chips 12 are picked up, one at a time, from an electronic component feeding device or chip feeding device 14 in which chips are disposed at the leading end of tapes, transferred, and located in position above a printed board by a manipulator. The manipulator comprises a head 22 and a cable rack chain 24 for moving the head 22 horizontally and at the same time transferring electric power and signals. At that time, the head 22 having a moving range as shown by arrow A picks up the chip 12 at the position as shown by arrow 22a, thereafter is moved horizontally, and mounts the chip 12 on the printed board 18 at the position as shown by arrow 22b. 
Since these operations are carried out in a space above the printed board, the foreign materials 20 such as dust or the like emanated from working parts and power feeding portion of manipulator of chip mounter fall down and are accumulated on the upper surface of the printed board.
Conventionally, since the electronic components were large in size, compared with the foreign materials 20 such as dust or the like, there was no problem. However, recently, since the electronic components are miniaturized very much, interference by the foreign materials 20 has been caused. For example, as shown in FIG. 5, when the foreign material 20 such as dust or the like which are large to a degree that interference may be caused are intervened between the electrode 12a of, for example, 0.1 mm in length of the electronic component 12 of, for example, 0.4 mm in length and the electrode 18a of, for example, 0.1 mm in length of the printed board 18, the defect in soldering would occur.
Therefore, it is an object of the present invention to provide a chip mounter which can inhibit accumulation of the foreign materials such as dust or the like to prevent the defect in soldering.